Puzzle page introduced by problem about time (5)
I believe the answer is:
stump
'puzzle' is the definition.
(thesaurus)
'page introduced by problem about time' is the wordplay.
'page' becomes 'p'.
'introduced by' says to put letters next to each other.
'problem' becomes 'sum' (arithmetic problem**).
'about' indicates putting letters inside.
'time' becomes 't'.
'sum' going around 't' is 'stum'.
'p' after 'stum' is 'STUMP'.
(Other definitions for stump that I've seen before include "Part of a felled tree that's left in the ground" , "Flummox" , "A single wicket" , "supporter of bail" , "Floor" .)